At least 11 people have died as a result of the blizzard that dropped up to two feet of snow in parts of the northeastern U.S. over Thursday night, as officials predicted even colder air would blow in over the weekend.

The dead include a road worker who was killed by a falling pile of road salt outside Philadelphia; a 79-year-old woman with Alzheimer’s who wandered away from home in western New York; and a 12-year-old car passenger killed when the 14-year-old driver crashed on a slick road in Michigan, the Associated Press reports.

Icy roads snarled traffic and led to accidents from Michigan, where a crude oil tanker crashed and set off a toxic fire, to Connecticut, where state police reported 225 crashes by Friday morning. Schools were closed across the midwest and northeast Friday, including the country’s largest school system in New York City, where newly-minted mayor Bill de Blasio faced an early test of his administrative acumen in dealing with the storm. The website FlightAware reported 2,325 flights canceled in the United States Friday.

The National Weather Service warned Friday of subzero temperatures and dangerous wind chills in the wake of the storm. “Some of the coldest air of the year should arrive by the weekend over the northern tier of the country,” it said. The freezing air and wind gusts exceeding 30 mph forecasted for the weekend is expected to send wind chill temperatures in Washington, DC, to near zero, and in North Dakota and Minnesota to -50 below, CNN reports.

Connecticut Gov. Dannel Malloy said Friday that wintery conditions are expected to recur in the coming weeks. “We’re going to see a warmup, and then we’re going to see another cold snap,” he said. “This may be something that we’re dealing with for the next 60 days or so.”